Over the past decade, compositionists have made a number of claims about opportunities presented by Wikipedia for teaching writing. The encyclopedia allows for transparent observation of concepts and skills related to process, research, collaboration, and rhetoric. Beyond observation, Wikipedia allows for public writing with an authentic audience, which often results in increased motivation. Much of this early research has dealt in opportunities and possibilities: speculation about how Wikipedia sponsors particular pedagogies and learning outcomes, and there remains a need for more empirical evidence. This article presents select data from a recent large-scale study conducted by the Wiki Education Foundation that begins to meet this need, and that confirms and extends research from the computers and writing community. Key findings from this research include positive evaluations of Wikipedia-based assignments in general, as well as positive evaluations concerning the capacity of Wikipedia-based assignments to teach critical thinking skills, source evaluation and research, public writing, literature review and synthesis, and peer review. This study also adds significantly to our field's knowledge of how contextual factors related to the course and assignment affect students’ evaluation of a Wikipedia-based assignment. Finally, this article suggests key recommendations for teaching with Wikipedia based on these findings.